CN107701662B

CN107701662B - Apparatus and method for distributing torque in worm and worm gear assembly

Info

Publication number: CN107701662B
Application number: CN201710733419.1A
Authority: CN
Inventors: N·A·赫尔曼; R·布鲁恩
Original assignee: Nidec Motors and Actuators Germany GmbH
Current assignee: Nidec Motors and Actuators Germany GmbH
Priority date: 2016-08-09
Filing date: 2017-08-09
Publication date: 2021-12-03
Anticipated expiration: 2037-08-09
Also published as: CN107701662A; US10281037B2; US20180045308A1; DE102017118119A1

Abstract

The invention relates to an apparatus and method for distributing torque in a worm and worm gear assembly. The worm and worm gear assembly may include: an input shaft having first and second worms axially formed thereon; a first torque transfer unit comprising a first worm gear operatively coupled to the first worm, a first radial pinion coaxially secured to the first worm gear, and a first axial crown operatively coupled to the first radial pinion; and a second torque transfer unit comprising a second worm wheel operatively coupled to the second worm, a second radial pinion coaxially secured to the second worm wheel, and a second axial crown operatively coupled to the second radial pinion, the first radial pinion forming a meshing interface with the second radial pinion, and a torque differential between the first axial crown and the second axial crown being at least partially transferred via the meshing interface.

Description

Apparatus and method for distributing torque in worm and worm gear assembly

Technical Field

Various embodiments are generally directed to worm and worm-gear assemblies and methods for distributing torque in worm and worm-gear assemblies.

Background

The gear assembly typically includes a drivable gear that is engaged by a driven gear to transmit torque. The gear assembly may be used to vary the speed, torque, and direction of the power source based on the configuration of the gear system. Various gear transmission systems, such as planetary gears, spur gears, worm gears, helical gears, and the like, are assembled and manufactured according to specific outputs, such as torque values, output directions, speeds, and space limitations.

Some gear assemblies (e.g., planetary or spur gears) have an axial output that coincides with the axis of the actuator shaft. However, because gear assemblies such as planetary gears or spur gears have high speeds in the mating gears between the drivable gear and the driven gear, these gear assemblies are very noisy. Additionally, if an axial dual output is desired, two different planetary gear assemblies are required. Therefore, a relatively large amount of space is required to achieve specific output requirements (such as axial dual output).

Although there are special planetary gear trains that are used to improve these negative aspects, the gear trains may not meet specific output requirements. Furthermore, the price of planetary gear transmission systems is relatively high and limited to a particular industry (such as the automotive industry). More particularly, in actuation applications involving moving components such as skylights, collapsible ceilings, or other moving components, quiet, robust, reliable, and relatively inexpensive drive solutions are desired.

Disclosure of Invention

The following examples relate to aspects of the disclosure:

example 1 is a worm and worm-gear assembly comprising: an input shaft having first and second worms axially formed thereon; a first torque transfer unit comprising a first worm gear operatively coupled to the first worm, a first radial pinion coaxially secured to the first worm gear, and a first axial crown operatively coupled to the first radial pinion; and a second torque transfer unit comprising a second worm gear operatively coupled to the second worm, a second radial pinion coaxially secured to the second worm gear, and a second axial crown operatively coupled to the second radial pinion, wherein the first radial pinion forms a meshing interface with the second radial pinion, and wherein a torque differential between the first axial crown and the second axial crown is at least partially transferred via the meshing interface.

In example 2, the subject matter of example 1 can optionally include: the first radial pinion gear having spur gears disposed on a radial periphery thereof; and said first axial crown wheel has on its axial periphery a crown wheel meshing with said spur gear of said first radial pinion.

In example 3, the subject matter of example 1 can optionally include: the second radial pinion gear having spur gears disposed on a radial periphery thereof; and said second axial crown wheel has on its axial periphery a crown wheel meshing with said spur gear of said second radial pinion.

In example 4, the subject matter of example 1 can optionally further comprise: a first output shaft coaxially connected to said first axial crown wheel; and a second output shaft coaxially connected to the second axial crown.

In example 5, the subject matter of any of examples 1-4 can optionally include: the worm and worm-gear assembly is configured to have an axial dual output.

In example 6, the subject matter of example 1 can optionally include: the first and second worms on the input shaft comprise two opposing worm-tooth systems.

In example 7, the subject matter of example 6 can optionally include: the two opposing worm gear systems allow the direction of rotation of the first axial crown and the direction of rotation of the second axial crown to be the same.

In example 8, the subject matter of example 6 can optionally include: the two opposing worm gear systems counteract the axial force.

In example 9, the subject matter of any of examples 1-4 can optionally include: the worm and worm gear assembly is configured to maintain a force within the worm drive up to 50% of the desired torque.

In example 10, the subject matter of any of examples 1-6 can optionally include: the first and second worms are manufactured as single start worms.

In example 11, the subject matter of any of examples 1-6 can optionally include: the input shaft is coaxially connected to a rotary motor.

In example 12, the subject matter of example 4 can optionally include: the first output shaft and the second output shaft are parallel to the input shaft.

In example 13, the subject matter of example 11 can optionally include: the first output shaft and the second output shaft are parallel to an axis of the rotary motor.

In example 14, the subject matter of any of examples 1-4 can optionally include: wherein the first worm gear comprises a plastic material.

In example 15, the subject matter of any of examples 1-4 can optionally include: the second worm gear comprises a plastic material.

In example 16, the subject matter of any of examples 1-4 can optionally include: the first radial pinion gear comprises a plastic material.

In example 17, the subject matter of any of examples 1-4 can optionally include: the second radial pinion gear comprises a plastic material.

In example 18, the subject matter of any of examples 1-4 can optionally include: the first worm gear and the first radial pinion constitute a single piece.

In example 19, the subject matter of any of examples 1-4 can optionally include: the second worm gear and the second radial pinion constitute a single piece.

In example 20, the subject matter of any of examples 1-19 can optionally include: the gearbox is configured to include the worm and worm gear assembly.

In example 21, the subject matter of example 20 can optionally include: the gearbox has a relatively small size.

In example 22, the subject matter of any of examples 1-9 can optionally include: the worm-and-worm gear assembly is configured to allow the first radial pinion gear and the second radial pinion gear to rotate with a relatively high torque.

In example 23, the subject matter of example 22 can optionally include: the relatively high torque has a value of at least 8 Nm.

In example 24, the subject matter of any of examples 1-4 can optionally include: the worm and worm gear assembly is configured to achieve low gear noise.

In example 25, the subject matter of any of examples 1-9 can optionally include: the worm-and-worm gear assembly is configured to achieve high gear strength of each worm by sharing the load on two gear lines having a large number of teeth to ensure large tooth overlap.

In example 26, the subject matter of any of examples 1-9 can optionally include: the worm-and-worm gear assembly is configured to achieve high gear strength of the spur gear by sharing forces among the two outputs and a large module with large teeth.

Example 27 is a worm and worm-gear assembly comprising: an input shaft having first and second worms axially formed thereon; a first torque transfer unit including a first worm gear operatively coupled to the first worm, a first radial pinion having a spur gear disposed on a radial periphery thereof, a first axial crown having a crown gear on an axial periphery thereof in meshing engagement with the spur gear of the first radial pinion; and a second torque transfer unit comprising a second worm wheel operatively coupled to the second worm, a second radial pinion coaxially secured to the second worm wheel and having a spur gear arranged on a radial periphery thereof, a second axial crown wheel having a crown gear on an axial periphery thereof in meshing engagement with the spur gear of the second radial pinion, wherein a first output shaft is coaxially connected to the first axial crown wheel and a second output shaft is coaxially connected to the second axial crown wheel, wherein the spur gear of the first radial pinion forms a meshing interface with the spur gear of the second radial pinion, and wherein a torque difference between the first output shaft and the second output shaft is at least partially transferred via the meshing interface.

In example 28, the subject matter of example 27 can optionally include: the worm and worm-gear assembly is configured to have an axial dual output.

In example 29, the subject matter of example 27 can optionally include: the first and second worms on the input shaft comprise two opposing worm-tooth systems.

In example 30, the subject matter of example 29 can optionally include: the two opposing worm gear systems allow the direction of rotation of the first axial crown and the direction of rotation of the second axial crown to be the same.

In example 31, the subject matter of any of examples 29 to 30 can optionally include: the two opposing worm gear systems counteract the axial force.

In example 32, the subject matter of any of examples 27 to 31 can optionally include: the worm and worm gear assembly is configured to maintain a force within the worm drive up to 50% of the desired torque.

In example 33, the subject matter of any of examples 27 to 32 can optionally include: the first and second worms are manufactured as single start worms.

In example 34, the subject matter of example 27 can optionally include: the input shaft is coaxially connected to a rotary motor.

In example 35, the subject matter of example 27 can optionally include: the first output shaft and the second output shaft are parallel to the input shaft.

In instance 36, the subject matter of instance 34 can optionally include: the first and second output shafts are parallel to an axis of the rotary motor.

In example 37, the subject matter of example 27 can optionally include: the first worm gear comprises a plastic material.

In example 38, the subject matter of example 27 can optionally include: the second worm gear comprises a plastic material.

In example 39, the subject matter of example 27 can optionally include: the first radial pinion gear comprises a plastic material.

In example 40, the subject matter of example 27 can optionally include: the second radial pinion gear comprises a plastic material.

In example 41, the subject matter of example 27 can optionally include: the first worm gear and the first radial pinion constitute a single piece.

In example 42, the subject matter of example 27 can optionally include: the second worm gear and the second radial pinion constitute a single piece.

In example 43, the subject matter of any of examples 27 to 42 can optionally include: the gearbox is configured to include the worm and worm gear assembly.

In example 44, the subject matter of example 43 can optionally include: the gearbox has a relatively small size.

In example 45, the subject matter of any of examples 27 to 32 can optionally include: the worm-and-worm gear assembly is configured to allow the first radial pinion gear and the second radial pinion gear to rotate with a relatively high torque.

In example 46, the subject matter of example 45 can optionally include: the higher torque is at least 8 Nm.

In example 47, the subject matter of example 27 can optionally include: the worm and worm gear assembly is configured to achieve low gear noise.

In example 48, the subject matter of any of examples 27 to 32 can optionally include: the worm-and-worm gear assembly is configured to achieve high gear strength of each worm by sharing the load on two gear lines having a large number of teeth to ensure large tooth overlap.

In example 49, the subject matter of any of examples 27 to 32 can optionally include: the worm-and-worm gear assembly is configured to achieve high gear strength of the spur gear by sharing forces among the two outputs and a large module with large teeth.

Example 50 is a method of distributing torque in a worm and worm-gear assembly, the method comprising the steps of: providing an input shaft on which a first worm and a second worm are axially formed; operatively coupling a first worm gear to the first worm; coaxially securing a first radial pinion to the first worm gear, wherein the first radial pinion has a spur gear disposed on a radial perimeter thereof; engaging a first axial crown wheel with the spur gear of the first radial pinion, wherein the first axial crown wheel has a crown gear on its axial perimeter; operatively coupling a second worm gear to the second worm; coaxially securing a second radial pinion to the second worm gear, wherein the second radial pinion has spur gears disposed on a radial perimeter thereof; engaging a second axial crown wheel with the spur gear of the second radial pinion, wherein the second axial crown wheel has a crown gear on its axial perimeter; coupling the spur gear of the first radial pinion to the spur gear of the second radial pinion in the form of a meshing interface, wherein a torque differential between the first and second axial crowns is at least partially transmitted via the meshing interface.

In example 51, the subject matter of example 50 can optionally further comprise: coaxially connecting a first output shaft to said first axial crown wheel; and coaxially connecting a second output shaft to the second axial crown wheel.

In example 52, the subject matter of any of examples 50-51 can optionally include: the worm and worm-gear assembly is configured to have an axial dual output.

In example 53, the subject matter of any of examples 50-51 can optionally include: the first and second worms on the input shaft comprise two opposing worm-tooth systems.

In example 54, the subject matter of example 53 can optionally include: the two opposing worm gear systems allow the direction of rotation of the first axial crown and the direction of rotation of the second axial crown to be the same.

In example 55, the subject matter of example 53 can optionally include: the two opposing worm gear systems counteract the axial force.

In example 56, the subject matter of any of examples 50-51 can optionally include: the worm and worm gear assembly is configured to maintain a force within the worm drive up to 50% of the desired torque.

In example 57, the subject matter of any of examples 50-53 can optionally include: the first and second worms are manufactured as single start worms.

In example 58, the subject matter of any of examples 50-51 can optionally include: the input shaft is coaxially connected to a rotary motor.

In example 59, the subject matter of example 51 can optionally include: the first output shaft and the second output shaft are parallel to the input shaft.

In example 60, the subject matter of example 58 can optionally include: the first output shaft and the second output shaft are parallel to an axis of the rotary motor.

In example 61, the subject matter of any of examples 50-51 can optionally include: the first worm gear comprises a plastic material.

In example 62, the subject matter of any of examples 50-51 can optionally include: the second worm gear comprises a plastic material.

In example 63, the subject matter of any of examples 50-51 can optionally include: the first radial pinion gear comprises a plastic material.

In example 64, the subject matter of any of examples 50-51 can optionally include: the second radial pinion gear comprises a plastic material.

In example 65, the subject matter of any of examples 50-51 can optionally include: the first worm gear and the first radial pinion constitute a single piece.

In example 66, the subject matter of any of examples 50-51 can optionally include: the second worm gear and the second radial pinion constitute a single piece.

In example 67, the subject matter of any of examples 50-66 can optionally include: the gearbox is configured to include the worm and worm gear assembly.

In example 68, the subject matter of example 67 can optionally include: the gearbox has a relatively small size.

In example 69, the subject matter of any of examples 50-56 can optionally include: the worm-and-worm gear assembly is configured to allow the first and second radial pinions to rotate with a relatively high torque.

In example 70, the subject matter of example 69 can optionally include: the relatively high torque is at least 8 Nm.

In example 71, the subject matter of any of examples 50-51 can optionally include: the worm and worm gear assembly is configured to achieve low gear noise.

In example 72, the subject matter of any of examples 50-56 can optionally include: the worm-and-worm gear assembly is configured to achieve high gear strength of each worm by sharing the load on two gear lines having a large number of teeth to ensure large tooth overlap.

In example 73, the subject matter of any of examples 50-56 can optionally include: the worm-and-worm gear assembly is configured to achieve high gear strength of the spur gear by sharing forces among the two outputs and a large module with large teeth.

In example 74, the subject matter of any of examples 1, 27, and 50 can optionally include: at least one of the first and second worms has a lead angle configured to prevent reverse actuation of the worm-and-worm gear assembly.

In example 75, the subject matter of example 74 can optionally include that the at least one of the first worm and the second worm has a lead angle of 5 degrees or less.

Drawings

In the drawings, like numerals generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the accompanying drawings, in which:

FIG. 1 illustrates a plan view of a worm and worm gear assembly in an engaged state in accordance with an aspect of the present disclosure;

FIG. 2 shows a front view of the worm and worm gear assembly;

FIG. 3 shows a schematic cross-sectional view taken along line A-A of FIG. 1;

FIG. 4 illustrates a method for distributing torque in a worm and worm-gear assembly in accordance with an aspect of the present disclosure.

Detailed Description

The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. Fig. 1 is a plan view illustrating a worm and worm wheel assembly 100 in an embodiment of the present disclosure. Fig. 2 is a front view illustrating the worm and worm wheel assembly 100 illustrated in fig. 1. Fig. 3 is a schematic sectional view illustrating a cross-sectional structure of the worm and worm wheel assembly 100 illustrated in fig. 1.

As illustrated in fig. 1-3, a worm and worm gear assembly 100 is used to distribute torque. Advantageously, the worm-and-worm gear assembly 100 is a step-down transmission because it reduces speed and increases torque, however other transmissions or device gear ratios are expressly contemplated in this disclosure. According to another advantageous aspect, the worm-and-worm-gear assembly 100 may be configured to operate in a manner that does not develop an axial force or load at the input shaft 120 due to reaction forces thereon. According to other advantageous aspects shown, the worm and worm-gear assembly 100 is configured to operate quietly and smoothly. In particular, the worm and worm-gear assembly 100 of the present invention is depicted as a double worm gear pair system having two opposing worm-gear systems 140 as shown in FIG. 1. The worm-and-worm-gear assembly 100 is shown with a double worm gear pair system configured to perform axial double output in the same rotational direction. This configuration and others in accordance with the present disclosure apply the system to a variety of industries, including the automotive industry. In particular, the worm and worm gear assembly 100 may be applied to some parts of a vehicle, such as a sunroof, a seat adjustment, or a trunk lid.

In fig. 1, the worm and worm gear assembly 100 of this embodiment includes an input shaft 120, a first torque transmission unit 150, and a second torque transmission unit 250. As illustrated in fig. 1, the input shaft 120 has two opposing worm-gear systems 140, such as a first worm 102 and a second worm 202. The first worm 102 and the second worm 202 are shown as being formed axially on the input shaft 120.

The input shaft 120 is connected to a power source (such as a mechanical power source). According to an aspect of the present disclosure, the power source may generate a force that may be applied or transmitted to the input shaft 120. An exemplary power source is shown as a rotary motor 130 that may be connected with the input shaft 120, such as by splines or a common shaft. Thus, the input shaft 120 may transmit power from a power source to the worm-and-gear assembly 100.

As illustrated in fig. 1, the input shaft 120 has a first worm 102 and a second worm 202. The first worm 102 and the second worm 202 are formed axially on the input shaft 120 and are two opposing worm-tooth systems 140, i.e. each worm is oppositely threaded to the other worm, i.e. of opposite handedness. Further, the first worm 102 and the second worm 202 are formed on the input shaft 120 with a distance d therebetween, as shown in fig. 1. The distance d is determined by the shortest gap between the first worm gear 104 and the second worm gear 204 in the x-direction (see fig. 1). The first worm 102 and the second worm 202 may be single start worms. However, as will be appreciated, a multi-start worm may be advantageous in certain applications, depending on the desired gearing, as the multi-start worm provides a different gear ratio than the single start worm.

The worm of one start advantageously has a lead distance equal to its pitch, but a relatively small lead angle. For example, the lead angle may be less than 5 degrees. This may be an advantage when it is desired to eliminate any possibility of output drive input. The transmission may be configured such that any torque reversal on the output shaft will result in immediate locking of the worm drive. Worm drives are generally used for this purpose and the worm wheel is often driven by a single-start worm with such a low lead angle that cannot be driven in reverse; that is, the

worm gear

104, 204 cannot drive the

worm

102, 202 because the transmission automatically locks itself against rearward rotation. This operational characteristic of the worm and worm gear assembly 100 may be desirable in many applications, such as sunroof or seat recliner adjustments in vehicles, and may be necessary in certain applications, for example, for passenger safety reasons.

As illustrated in fig. 1 and 3, the first torque transmission unit 150 includes a first worm gear 104, a first radial pinion gear 106, and a first axial crown gear 108. Advantageously, the first worm gear 104 is operatively coupled to the first worm 102. As shown, the first radial pinion gear 106 is coaxially secured to the first worm gear 104, such as by attachment. That is, they may be coaxially fixed to each other such that they rotate in unison about the same axis. A first axial crown 108 is operatively coupled to the first radial pinion 106.

In fig. 1, the first worm gear 104 is shown engaged with a first worm 102 formed axially on the input shaft 120. The first worm gear 104 has a system of teeth, and the system of teeth on the first worm gear 104 is configured to be operatively coupled to, that is, meshed with, the system of teeth on the first worm 102. Thus, the first worm 102 actuates the first worm gear 104 and transmits a rotational force to the first worm gear 104 having a rotational axis different from the rotational axis of the input shaft 120. In particular, the input shaft 120 is shown as rotating about an axis in the x-direction, while the first worm gear 104 is driven by the first worm 102 about an axis oriented in the z-direction (see fig. 2). Due at least in part to the aforementioned interaction of the first worm gear 104 with the first worm 102 having the single start configuration, the gearing having the first worm 102 and the first worm gear 104 may reduce rotational speeds and transmit higher torques.

The first worm gear 104 may be made of a different material such as plastic or metal (such as steel). According to one aspect of the present disclosure, the first worm gear 104 may be made of a plastic material (particularly a strong plastic).

As illustrated in fig. 1 and 3, a first radial pinion gear 106 is coaxially secured to the first worm gear 104. The first radial pinion 106 is shown as being directly attached to the first worm gear 104, or integrally formed with the first worm gear 104. Alternatively, the first radial pinion gear 106 may be separately attached to the first worm gear 104 by a connecting piece (such as a splined rod at the center of the two wheels). In each case, the result is that both the first radial pinion 106 and the first worm gear 104 rotate in unison.

The diameter of the first radial pinion gear 106 is greater than the diameter of the first worm gear 104, as shown in fig. 1 and 3. In accordance therewith, a tooth system 116 formed on the periphery of the first radial pinion 106 extends radially outward from the worm drive 114 on the periphery of the first worm gear 104.

The first radial pinion 106 may also be made of a different material, such as plastic or metal (such as steel). According to an aspect of the present disclosure, the first radial pinion 106 may be made of a plastic material, in particular a strong plastic. Additionally, where the first worm gear 104 and the first radial pinion 106 are made of the same material and are axially secured together, the first worm gear 104 and the first radial pinion 106 may be made from a single piece that is formed together via injection molding.

As illustrated in fig. 3, the first axial crown 108 is operatively coupled to the first radial pinion gear 106. The first radial pinion 106 actuates the first axial crown 108, in particular the first radial pinion 106 is illustrated as meshing with the first axial crown 108. Because the first axial crown 108 has a tooth system 118 that engages at an angle with a corresponding tooth system 116 on the first radial pinion 106, the rotational output of the first radial pinion 106 is changed to a different direction in the first axial crown 108. Thus, the direction of torque in the worm-and-worm-gear assembly 100 is changed by engagement of the tooth system on both wheels.

In fig. 3, another aspect of the present disclosure is illustrated. In particular, the tooth system 116 on the first radial pinion 106 may take the form of a spur gear. The spur gears on the first radial pinion 106 are disposed on the radial perimeter of the first radial pinion 106. Additionally, the tooth system 118 on the first axial crown 108 may take the form of a crown wheel. The crown wheel on the first axial crown wheel 108 is arranged on the axial periphery of the first axial crown wheel 108. The crown gear of the first axial crown gear 108 meshes with the spur gear of the first radial pinion gear 106. Thus, the first axial crown 108 is actuated by the gear transmission system engaged in the axial crown 106 and the radial pinion 108, and the direction of the torque in the first axial crown 108 is changed accordingly.

As illustrated in fig. 1 and 3, the second torque transmission unit 250 is provided to have the same or similar parallel configuration as the first torque transmission unit 150. In particular, second torque transfer unit 250 includes a second worm gear 204, a second radial pinion gear 206, and a second axial crown 208. Advantageously, the second worm gear 204 is operatively coupled to the second worm 202. As shown, the second radial pinion 206 is coaxially secured to the second worm gear 204, such as by attachment. That is, they may be coaxially fixed to each other such that they rotate in unison about the same axis. Second axial crown 208 is operatively coupled to second radial pinion gear 206.

In fig. 1, the second worm gear 204 is shown engaged with a second worm 202 formed axially on the input shaft 120. The second worm gear 204 has a system of teeth, and the system of teeth on the second worm gear 204 is configured to be operatively coupled to, that is, meshed with, the system of teeth on the second worm 202. Thus, the second worm 202 actuates the second worm gear 204 and transmits the rotational force to the second worm gear 204 having a rotational axis different from the rotational axis of the input shaft 120. In particular, the input shaft 120 is shown as rotating about an axis in the x-direction, while the second worm gear 204 is driven by the second worm 202 about an axis oriented in the z-direction (see fig. 2). Due at least in part to the aforementioned interaction of the second worm gear 204 with the second worm 202 having the single start configuration, the gearing having the second worm 202 and the second worm gear 204 may reduce rotational speeds and transmit higher torques.

The second worm gear 204 may be made of a different material such as plastic or metal (such as steel). According to one aspect of the present disclosure, the second worm gear 204 may be made of a plastic material (particularly a strong plastic).

As illustrated in fig. 1 and 3, a second radial pinion gear 206 is coaxially secured to the second worm gear 204. The second radial pinion 206 is shown as being directly attached to the second worm gear 204, or integrally formed with the second worm gear 204. Alternatively, the second radial pinion gear 206 may be separately attached to the second worm gear 204 by a connecting piece (such as a splined rod at the center of the two wheels). In each case, the result is that both the second radial pinion gear 206 and the second worm gear 204 rotate in unison.

The diameter of the second radial pinion gear 206 is greater than the diameter of the second worm gear 204, as shown in fig. 1 and 3. In accordance therewith, a tooth system 216 formed on the perimeter of the second radial pinion gear 206 extends radially outward from the worm drive 214 on the perimeter of the second worm gear 204.

The second radial pinion 206 may also be made of a different material, such as plastic or metal (such as steel). According to an aspect of the present disclosure, the second radial pinion 206 may be made of a plastic material, in particular a strong plastic. Additionally, the second worm gear 204 and the second radial pinion 206 may be made from a single piece formed together via injection molding, as the second worm gear 204 and the second radial pinion 206 may be made from the same material and axially secured together.

As illustrated in fig. 3, second axial crown 208 is operatively coupled to second radial pinion gear 206. Second radial pinion 206 actuates second axial crown 208, and in particular second radial pinion 206 is illustrated as meshing with second axial crown 208. Because second axial crown 208 has a tooth system 218 that engages at an angle with a corresponding tooth system 216 on second radial pinion 206, the rotational output of second radial pinion 206 is changed to a different direction in second axial crown 208. Thus, the direction of torque in the worm-and-worm-gear assembly 100 is changed by engagement of the tooth system on both wheels.

In fig. 3, another aspect of the present disclosure is illustrated. In particular, the tooth system 216 on the second radial pinion 206 may take the form of a spur gear. The spur gears on the second radial pinion 206 are disposed on the radial perimeter of the second radial pinion 206. Additionally, the tooth system 218 on the second axial crown 208 may take the form of a crown wheel. The crown wheel on the second axial crown wheel 208 is arranged on the axial periphery of the second axial crown wheel 208. The crown gear of the second axial crown 208 meshes with the spur gear of the second radial pinion 206. Thus, the second axial crown 208 is actuated by the gear train engaged in the second axial crown 206 and the radial pinion 208, and the direction of torque in the second axial crown 208 is changed accordingly.

As shown in fig. 1 to 3, the worm and worm-gear assembly 100 further includes a first output shaft 110 and a second output shaft 210. First output shaft 110 is coaxially connected to first axial crown wheel 108, and second output shaft 210 is coaxially connected to second axial crown wheel 208. Each

output shaft

110, 210 may be directly attached to each

axial crown wheel

108, 208 or indirectly attached to each

axial crown wheel

108, 208 via a connecting part. With first output shaft 110 and second output shaft 210 coaxially attached to first axial crown wheel 108 and second axial crown wheel 208, the rotational speed of each

output shaft

110, 210 remains the same as the rotational speed of each

axial crown wheel

108, 208. Thus, the first output shaft 110 and the second output shaft 210 need not be directly connected to each other due to the meshing interface between the first radial pinion 106 and the second radial pinion 206.

As illustrated in fig. 1 and 3, the first and

second worms

102, 202 engage with the worm gears 114, 214 on the first and second worm gears 104, 204. As described above, the first worm 102 and the second worm 202 have two opposing worm-tooth systems 140. Accordingly, the first and

second worms

102, 202 are operatively coupled to the first and second worm gears 104, 204. The worm drives 114, 214 on the two

worm wheels

104, 204 also have an opposite tooth system, depending on the opposite screwing direction of each

worm

102, 202. The two

worm gears

104, 204 and the coaxially mounted

radial pinions

106, 206 allow for different directions of rotation in the two

worm gears

104, 204 due to the opposing tooth systems. As a result, first axial crown wheel 108 and second axial crown wheel 208 may rotate in the same axial direction. Therefore, the worm-and-worm-gear assembly 100 is configured to perform axial dual output in the same direction.

Further, as illustrated in fig. 3, the first radial pinion 106 interfaces with the second radial pinion 206. The meshing interface between the first radial pinion 106 and the second radial pinion 206 is necessary for the worm and worm-gear assembly 100 to decouple incoming unilateral forces on the input shaft 120. Accordingly, the worm-and-worm-gear assembly 100 is configured to require a meshing interface between the first radial pinion 106 and the second radial pinion 206. Additionally, a torque differential between first axial crown wheel 108 and second axial crown wheel 208 is at least partially transmitted via the meshing interface. In particular, the transfer of torque may be in either direction, i.e. from the first torque transfer unit 150 to the second torque transfer unit 250 in case the load on the second output shaft 210 exceeds the load on the first output shaft 110, or in the opposite direction in case the imbalance of the loads is opposite. Also, where reaction forces are considered, the transfer of reaction forces between the units will thus be opposed to the torque transfer discussed immediately above. Thus, the worm-and-worm gear assembly 100 of the present invention is configured to have an axial dual output, as the two different outputs in each

axial crown

108, 208 can rotate in the same direction. This arrangement allows the force to be distributed between the components of the worm and worm-gear assembly 100 such that, among other advantages, the concentration of load on either of the

worms

102 or 202 is reduced to the exclusion of the other. Thus, because the forces are more evenly distributed among them, the worm gears 104, 204 need not be designed to withstand the same amount of force that would otherwise be necessary to prevent failure of the interface between the worm gear and the corresponding worm. This allows for a cheaper and/or more compact design.

Because the opposing tooth systems 140 on the first and

second worms

102, 202 allow different directions of rotation in the worm-and-gear assembly 100, the first and

second output shafts

110, 210 attached to the first and second

axial crown wheels

108, 208 may rotate in the same direction of rotation. Thus, the opposing tooth system 140 counteracts the axial force.

As illustrated in fig. 1, the first output shaft 110 and the second output shaft 210 on the axis C are parallel to the input shaft 120 on the axis B. Further, when the input shaft 120 is coaxially connected to one of the power sources (such as the rotary motor 130), the first output shaft 110 and the second output shaft 210 are also parallel to the motor axis.

According to one aspect of the present disclosure, the transmission is designed to include a worm and worm gear assembly 100 that is relatively small in size. According to other advantageous aspects, the worm-and-worm-gear assembly 100 is shown configured to have relatively high torque and force values even though the size of the gearbox is small. In particular, higher torque values can reach a maximum of 8 Nm.

According to one aspect of the present disclosure, high gear strength of the worm may be achieved by sharing the load on two gear lines with a large number of teeth to ensure large tooth overlap in a smaller given space. In the case of a unilateral load on the input shaft 120, the worm strength is shared by the two torque transfer units, since the first worm 102 and the second worm 202 are matched to each

worm wheel

104, 204, and with this gear matching, the force is split to the two

worms

102, 202. According to another advantageous aspect, a high gear strength of the crown wheel is achieved by sharing the forces in both outputs and a large module with large teeth.

Advantageously, the worm-and-worm-gear assembly 100 is configured to achieve low gear noise, since the first gear stage is a worm drive with low noise. The worm drive gear arrangement reduces the speed of the second sensitive crown gear which would otherwise be noisy driving at or near the drive input speed. According to an aspect of the present disclosure, the first radial pinion 106 including the first worm gear 104 and the second radial pinion 206 including the second worm gear 204 operate at a low speed in the latter stages of the gear assembly, thereby potentially significantly reducing noise. In addition, the

output shafts

110, 210 are parallel to the input shaft 120 in the worm-and-gear assembly 100. The constructional features of the present disclosure are much quieter than other parallel constructions of the input and output of the worm drive system, due to the combination of the interaction of the worm gear and the pinion operating at higher rotational speeds with the crown wheel transmission (at final drive). Thus, the present disclosure may advantageously reduce noise levels in previous configurations that tend to be noisier than comparable vertical arrangements.

The worm-and-worm-gear assembly 100 is configured to have an axial dual output that combines a higher force with a worm-and-worm-gear system in a smaller given space. The most important part of the worm and worm gear assembly 100 is the opposing worm gear system 140 on the input shaft 120 in combination with the meshing interface in the spur gear between the first radial pinion 106 and the second radial pinion 206. The configuration of the present disclosure allows for maintaining the force within the worm drive up to 50% of the desired torque.

Fig. 4 shows a schematic diagram illustrating a method 300 for distributing torque in the worm and worm-gear assembly 100 according to various embodiments. Details of the various processes may be described above.

As shown in fig. 4, the method 300 may include: providing an input shaft on which a first worm and a second worm (310) are axially formed; operatively coupling a first worm gear to a first worm (320); coaxially securing a first radial pinion gear to the first worm gear, wherein the first radial pinion gear has a spur gear (330) disposed on a radial periphery thereof; meshing a first axial crown wheel with a spur gear of a first radial pinion, wherein the first axial crown wheel has a crown gear (340) on its axial periphery; operatively coupling a second worm gear to a second worm (350); coaxially securing a second radial pinion to the second worm gear, wherein the second radial pinion has a spur gear (360) disposed on a radial periphery thereof; meshing a second axial crown wheel with a spur gear of a second radial pinion, wherein the second axial crown wheel has a crown wheel (370) on its axial periphery; coupling the spur gear of the first radial pinion to the spur gear of the second radial pinion in the form of a meshing interface, wherein a torque difference between the first and second axial crowns is partially transferred (380) via the meshing interface.

The method may further comprise: the first output shaft is coaxially connected to the first axial crown wheel and the second output shaft is coaxially connected to the second axial crown wheel (390).

While the present disclosure has been particularly shown and described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims. The scope of the disclosure is thus indicated by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A worm and worm-gear assembly, comprising:

an input shaft having first and second worms axially formed thereon;

a first torque transfer unit comprising:

a first worm gear operatively coupled to the first worm;

a first radial pinion coaxially secured to the first worm gear; and

a first axial crown operatively coupled to the first radial pinion; and

a second torque transfer unit comprising:

a second worm gear operatively coupled to the second worm;

a second radial pinion coaxially secured to the second worm gear; and

a second axial crown operatively coupled to the second radial pinion,

wherein the first radial pinion forms a meshing interface with the second radial pinion, and

wherein a torque differential between the first axial crown wheel and the second axial crown wheel is at least partially transferred via the meshing interface.

2. The worm and worm-gear assembly as recited in claim 1,

the first radial pinion gear having spur gears disposed on a radial periphery thereof; and is

The first axial crown wheel has on its axial periphery a crown wheel meshing with the spur gear of the first radial pinion.

3. The worm and worm-gear assembly as recited in claim 1,

the second radial pinion gear having spur gears disposed on a radial periphery thereof; and is

The second axial crown wheel has on its axial periphery a crown wheel meshing with the spur gear of the second radial pinion.

4. The worm and worm-gear assembly as recited in claim 1, further comprising:

a first output shaft coaxially connected to said first axial crown wheel; and

a second output shaft coaxially connected to the second axial crown.

5. The worm and worm-gear assembly as recited in claim 1,

the worm and worm-gear assembly is configured to have an axial dual output.

6. The worm and worm-gear assembly as recited in claim 1,

the first and second worms on the input shaft comprise two opposing worm-tooth systems.

7. The worm and worm-gear assembly as recited in claim 6,

the two opposing worm gear systems allow the direction of rotation of the first axial crown and the direction of rotation of the second axial crown to be the same.

8. The worm and worm-gear assembly as recited in claim 4,

the input shaft is coaxially connected to a rotary motor.

9. The worm and worm-gear assembly as recited in claim 8,

the first output shaft and the second output shaft are parallel to an axis of the rotary motor.

10. The worm and worm-gear assembly as recited in claim 1,

the first and second worm gears comprise a plastic material and the first and second radial pinions comprise a plastic material.

11. The worm and worm-gear assembly as recited in claim 1,

the first worm gear and the first radial pinion constitute a single piece.

12. The worm and worm-gear assembly as recited in claim 1,

the second worm gear and the second radial pinion constitute a single piece.

13. The worm and worm-gear assembly as recited in claim 1,

the worm and worm gear assembly is configured to achieve low gear noise.

14. A worm and worm-gear assembly, comprising:

an input shaft having first and second worms axially formed thereon;

a first torque transfer unit comprising:

a first worm gear operatively coupled to the first worm;

a first radial pinion coaxially secured to the first worm gear, the first radial pinion having a spur gear disposed on a radial periphery thereof;

a first axial crown wheel having on its axial periphery a crown wheel meshing with the spur gear of the first radial pinion; and

a second torque transfer unit comprising:

a second worm gear operatively coupled to the second worm;

a second radial pinion coaxially secured to the second worm gear, the second radial pinion having a spur gear disposed on a radial periphery thereof; and

a second axial crown wheel having on its axial periphery a crown wheel meshing with the spur gear of the second radial pinion,

wherein a first output shaft is coaxially connected to the first axial crown wheel and a second output shaft is coaxially connected to the second axial crown wheel;

wherein the spur gear of the first radial pinion forms a meshing interface with the spur gear of the second radial pinion; and is

Wherein a torque differential between the first output shaft and the second output shaft is at least partially transferred via the engagement interface.

15. The worm and worm-gear assembly as recited in claim 14,

the worm and worm-gear assembly is configured to have an axial dual output.

16. The worm and worm-gear assembly as recited in claim 14,

17. The worm and worm-gear assembly as recited in claim 14,

the input shaft is coaxially connected to a rotary motor, and the first output shaft and the second output shaft are parallel to an axis of the rotary motor.

18. The worm and worm-gear assembly as recited in claim 14,

the worm and worm gear assembly is configured to achieve low gear noise.

19. A method of distributing torque in a worm and worm-gear assembly, the method comprising the steps of:

providing an input shaft on which a first worm and a second worm are axially formed;

operatively coupling a first worm gear to the first worm;

a first radial pinion gear is coaxially secured to the first worm gear,

wherein the first radial pinion has spur gears disposed on a radial perimeter thereof;

engaging a first axial crown wheel with the spur gear of the first radial pinion,

wherein the first axial crown wheel has a crown wheel on its axial periphery;

operatively coupling a second worm gear to the second worm;

coaxially securing a second radial pinion to the second worm gear,

wherein the second radial pinion has spur gears disposed on a radial perimeter thereof;

engaging a second axial crown wheel with said spur gear of said second radial pinion,

wherein the second axial crown wheel has a crown wheel on its axial periphery; and

coupling the spur gear of the first radial pinion to the spur gear of the second radial pinion in a meshing interface,

20. The method of claim 19, the method further comprising:

coaxially connecting a first output shaft to said first axial crown wheel; and

coaxially connecting a second output shaft to said second axial crown wheel.